The invention involves an electrically driven pump, of the type consisting of at least one hydraulic pump, particularly with gears, set in revolving motion by a motor device.
Electrically driven pumps of this type, which are known and used in particular by the motor vehicle's power-assisted steering, exhibit the major inconvenience in that the unit's power is limited although the vehicles to be equipped with power-assisted steering are increasingly heavier and the power needed to ensure the power-assisted steering are increasingly higher. Whereas, currently the motor power output of electrically driven pumps is limited for technological reasons, in particular due to the fact that the feed and connector technology do not accept sufficient power, that the technology of high-powered motors (>1.5 kW) is nearly non-existent for a voltage of 12V and that the development of such motors is limited to a small series and represents a major cost.
The purpose of the invention is to get around the inconvenience of known systems.
To achieve this goal, the electrically driven pump according to the invention is characterized in that it consists of two hydraulic pumps and two electric motors that are fitted in such a way as to make it possible to obtain the unit's power by adding together the power of the two motors.
According to a characteristic of the invention, the electrically driven pump is characterized in that it includes a manifold of delivery that consists of a pressure passage common to two pumps.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the two pumps are integrated into one common pump housing.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that it includes a manifold of suction consisting of a suction passage common to two pumps.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the prime movers of the two pumps are positioned on either side of the common pump housing.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the pump housing is positioned sandwich-style between the manifold of suction and the manifold of delivery, each manifold carrying on its outer face one of the two motors.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the pump housing consists, on the inside of an outer casing wall, of a high pressure volume common to two pumps, which communicates with the working chambers of the two pumps and a common high pressure volume anticipated in the manifold of delivery, which is in communication with the common pressure passage.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that it includes a common supporting sole plate and on one face of which are mounted the two pumps and on the other the two motors.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the two pumps are enclosed in a common jacket likely to constitute a low-pressure liquid reservoir.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that at least one of the pumps consists, in its path of delivery, of a check valve so that this pump can be stopped selectively.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that it includes a motor piloting device 3 adapted to ensure the piloting of a motor from the outside and in that this motor controls the speed of the other.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the two motors turn in the same direction or in opposite directions.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the two pumps are adapted to turn with an angular displaying position of a few degrees to procure a reduction in pressure pulsations produced by the electrically driven pump.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the two pumps are likely to run opposite phases.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the pumps run at different rotating speeds.
According to yet another characteristic of the invention, the electrically driven pump is characterized in that the presence of two motors constitutes a means of safety by redundancy.